MERV (Minimum Efficiency Reporting Value) and HEPA (High Efficiency Particulate Air) are both standards used to measure the efficiency of air filters, but they differ in their specifications and applications.

MERV:

MERV is a rating system that classifies the effectiveness of air filters based on their ability to capture particles of different sizes. The scale typically ranges from 1 to 16, with higher values indicating better filtration efficiency.

MERV-rated filters are commonly used in residential and commercial HVAC (Heating, Ventilation, and Air Conditioning) systems. They are effective at capturing particles like dust, pollen, and mold, but they may not be as efficient at trapping very small particles.

HEPA:

HEPA, on the other hand, is a more stringent standard. To meet HEPA requirements, a filter must capture at least 99.97% of particles that are 0.3 micrometers in size. HEPA filters are highly effective at trapping a wide range of particles, including bacteria, viruses, and other microscopic contaminants.

HEPA filters are often used in environments where very high air quality is crucial, such as hospitals, laboratories, and cleanrooms. They are also used in certain residential air purifiers to provide a higher level of filtration.

In summary, while both MERV and HEPA standards measure the efficiency of air filters, HEPA filters have a higher level of efficiency and are capable of capturing smaller particles. MERV filters are more commonly found in HVAC systems, while HEPA filters are used in environments where extremely high air quality is essential.